Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 eac68823335f3b23…

MALICIOUS

Office (OLE) / .XLS

48.5 KB Created: 2020-10-21 08:13:35 Authoring application: Microsoft Excel
MD5: 73353c73c6daa38d28aadcdbbe5b3646 SHA-1: 5d6970c799fdefbe09d8622f26488684e7e45269 SHA-256: eac68823335f3b236befca2a33e676e643efb0e8b8d0c9cbcb1987ad54afbac0
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open function, which is a common technique for executing malicious code upon opening the document. The macro sheet contains a reference to 'RUN=0', suggesting it attempts to execute a command. The extensive obfuscated strings in the document body and the truncated script content prevent a more detailed analysis of the payload, but the primary intent appears to be the execution of a second-stage payload.

Heuristics 3

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
3fe428ca88ea3e69e267e59ff0d981ba73e93f2624818c83a78df6c392177a3d
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 12568 bytes